US president's comments come within days of landmark UN report warning of catastrophic risks posed by global warming.

US President Donald Trump has again expressed doubt over whether rising global temperatures are being caused by humanity and accused scientists studying climate change of pursuing a "political agenda".

In a "60 Minutes" interview with US-based broadcaster CBS aired on Sunday, Trump said any alterations to the earth's climate would "change back again".

"I will say this. I don't wanna give trillions and trillions of dollars. I don't wanna lose millions and millions of jobs. I don't wanna be put at a disadvantage," he added.

Trump has previously called climate change "a hoax" and said in November 2012 that the "concept of global warming was created by and for the Chinese in order to make US manufacturing non-competitive."

UN warnings

His comments on Sunday came less than a week after the publication of a landmark UN report which said "human activities" had already caused global warming of approximately one degree Celsius since pre-industrial times.

Keeping to the target of 1.5C of warming against pre-industrial levels agreed to in the internationally backed Paris climate change agreement of 2015 will mean "rapid, far-reaching and unprecedented changes in all aspects of society", it added.

Trump announced last year he would pull the US out of the pact, which set voluntary greenhouse gas emission targets in an effort to lessen the impact of fossil fuels, saying the agreement was "disadvantageous to the US to the exclusive benefits of other countries".

According to the rules of the Paris deal, the earliest date for the US to completely withdraw from the agreement is November 4, 2020, around the time of the next US presidential election.

'Willful ignorance'

Travis Nichols, media director for Greenpeace USA, said Trump's "willful ignorance" over climate change would have "profound consequences for the entire world".

"If these comments were made by some guy muttering on a street corner, it would be easy to dismiss them as the ravings of a delusional crank. Tragically, this is the president of the United States," Nichols said.

"We've reached the moment of truth in our fight against climate change, a defining moment for all of us - all generations - where our collective fate hangs in the balance," he added.

"There is no 'safe' level of warming, and there's no time to indulge fossil fuel stooges like Donald Trump in their science fiction fantasies."

Temperature records kept by the US space agency, NASA, and the US National Oceanic and Atmospheric Administration show that the world has not had a cooler-than-average year since 1976 or a cooler-than-normal month since the end of 1985.